FIB-4 Calculator

FIB-4 is a score calculated from four pieces of information you already have on a routine blood test: age, AST (TGO), ALT (TGP) and the platelet count. It estimates the likelihood that the liver has advanced fibrosis, that is significant scarring, without needing special investigations at this first stage. It is used as a triage test, particularly in people with fatty liver.

Below 1.3, the risk of advanced fibrosis is low, and the score can be repeated periodically. Between 1.3 and 2.67 is an indeterminate zone, where the doctor usually recommends an additional test, such as liver elastography (measuring liver stiffness with devices like FibroScan) [1]. Above 2.67, the risk is high and specialist assessment is needed. In people over 65, the lower cut-off used is 2.0 instead of 1.3, because age raises the score on its own [2].

Fatty liver associated with metabolic dysfunction (MASLD) is very common in people with type 2 diabetes and can progress silently to fibrosis. MASLD stands for metabolic dysfunction-associated steatotic liver disease; it was previously called non-alcoholic fatty liver disease. Current diabetes guidelines recommend calculating FIB-4 periodically in people with type 2 diabetes, or with prediabetes plus risk factors [3]. The aim is to identify early those who need further liver investigations. What ties the two together most often is the fat around the abdomen, and where it sits is shown by the waist-to-height ratio.

FIB-4 does not diagnose fibrosis; it only guides triage. In people under 35 it is less reliable, and transaminases can fluctuate for several reasons (medicines, alcohol, infections), which complicates interpreting the score. A result in the indeterminate or high zone does not mean you have fibrosis, only that further assessment is worthwhile. Discuss the result with your doctor.